BACKGROUND Morus boninensis, is an endemic plant of the Bonin (Ogasawara) Islands of Japan and is categorized as "critically endangered" in the Japanese red data book. However, little information is available about its ecological, evolutionary and genetic status, despite the urgent need for guidelines for the conservation of the species. Therefore, we adopted Moritz's MU concept, based on the species' current genetic structure, to define management units and to select mother tree candidates for seed orchards. RESULTS Nearly all individuals of the species were genotyped on the basis of seven microsatellite markers. Genetic diversity levels in putative natural populations were higher than in putative man-made populations with the exception of those on Otouto-jima Island. This is because a limited number of maternal trees are likely to have been used for seed collection to establish the man-made populations. A model-based clustering analysis clearly distinguished individuals into nine clusters, with a large difference in genetic composition between the population on Otouto-jima Island, the putative natural populations and the putative man-made populations. The Otouto-jima population appeared to be genetically differentiated from the others; a finding that was also supported by pairwise FST and RST analysis. Although multiple clusters were detected in the putative man-made populations, the pattern of genetic diversity was monotonous in comparison to the natural populations. CONCLUSION The genotyping by microsatellite markers revealed strong genetic structures. Typically, artificial propagation of this species has ignored the genetic structure, relying only on seeds from Otouto-jima for replanting on other islands, because of a problem with inter-specific hybridization on Chichi-jima and Haha-jima Islands. However, this study demonstrates that we should be taking into consideration the genetic structure of the species when designing a propagation program for the conservation of this species.

中文翻译：

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桑Mor残留的遗传结构测定。树木在日本波宁群岛上建立保护计划。

背景技术桑属桑属（Morus boninensis）是日本波宁（小gas原）群岛的特有植物，在日本红色数据手册中被列为“极度濒危”。然而，尽管迫切需要有关物种保护的准则，但关于其生态，进化和遗传状况的信息很少。因此，我们基于该物种当前的遗传结构采用了莫里茨的MU概念，以定义管理单位并选择种子树的母树候选对象。结果该物种的几乎所有个体都根据七个微卫星标记进行了基因分型。假定的自然种群的遗传多样性水平高于假定的人工种群，但奥图图岛岛上的除外。这是因为有限数量的母树可能已被用于收集种子以建立人工种群。基于模型的聚类分析清楚地将个体分为9个聚类，在Otouto-jima岛上的种群，假定的自然种群和假定的人工种群之间，遗传组成存在很大差异。奥图托岛人口似乎在遗传上与其他人不同。成对的FST和RST分析也支持这一发现。尽管在假定的人工种群中发现了多个簇，但是与自然种群相比，遗传多样性的模式是单调的。结论微卫星标记的基因分型显示出强大的遗传结构。通常，该物种的人工繁殖忽略了遗传结构，仅依靠奥图托岛的种子重新种植在其他岛屿上，因为在奇奇岛和哈哈岛上存在种间杂交的问题。但是，这项研究表明，在设计保护该物种的繁殖计划时，我们应该考虑该物种的遗传结构。